How to use string in java

String is an immutable sequence of characters in Java used to represent text data. It provides methods to manipulate strings, including the following points: creating String objects through literals or String constructors; operating Strings through string concatenation, search, replacement, and formatting methods; using the equals() method to compare two Whether the contents of the String are equal; use the parseXxx() or valueOf() method to convert the String to other types; note that String is immutable and string comparisons are case-sensitive. The StringBuilder class should be used for efficient string splicing.

Usage of String in Java

String is an immutable sequence of characters in Java used to represent text data. The String class provides methods for operating on strings, including string concatenation, search, replacement, and formatting.

1. Create a String object

There are two main ways to create a String object:

• String literal ): A set of characters enclosed in double quotes ("), such as "Hello World".
• String constructor: Use new keyword and String constructor, such as new String("Hello World").

##2. String operation#. ##String class provides various methods to operate strings:

String concatenation:
• Use operator or concat() Method to connect strings, such as "Hello" " " "World".
Find substrings:
• Use indexOf() Or the lastIndexOf() method finds the index of the specified substring, for example "Hello World".indexOf("World")Replace the subcharacters. String: Use the replace()
or
• replaceAll() method to replace the specified substring, for example "Hello World".replace("World", "Universe" ). Format string: Use the String.format()
method to format a string based on a placeholder, such as
• String. format("My name is %s", "John"). ##3. String comparison
can use

equals( )

method compares two String objects for equality. It compares the contents of the strings, not their references.

Can be converted to String. String objects are converted to other types, such as:

Basic types:

Use the parseXxx() method to convert String to basic types, such as

Integer .parseInt("123")

.

• Other objects: Use the valueOf() method to convert String to other objects, such as BigDecimal. valueOf("123.45").
• 5. Note that ##String object is immutable, which means that String The operation does not modify the original object, but returns a new String object. String comparison is case-sensitive.

Using the

operator for string concatenation should be avoided because it creates a new String object. A more efficient way is to use the StringBuilder

class.

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